An HSPA (high speed packet access) network is a network capable of providing high-speed uplink and downlink communication rates. An LTE (long term evolution) network is evolved from a current 3G network, and can improve performance of cell-edge users, improve cell capacity, and decrease a system delay. In a future communication network, a 3G network, an HSPA network, and an LTE network will coexist for a long period of time.
A user, who is performing a voice call in a 3G network, may move to an HSPA or LTE cell, so that the voice service needs to be handed over to a new system in order to maintain continuity of a voice service. In a current solution for implementing a seamless connection of voice and data services between a 3G network and HSPA and LTE networks, a source core network node MSC server (mobile switching center server) needs to determine whether a target system of handover is an LTE network system or an HSPA network system, and different security processing is performed for different target systems, but currently the MSC server does not have the discrimination capability.